Codeuteronomy
The request must be bounded; the unscoped will be invented
A vague ask is a large ask with the boundaries left for the agent to guess. It guesses wide.
A human colleague hears “clean this up a bit” and does the obvious minimum. An agent hears an open mandate: it renames files you never mentioned, adds config nobody wanted, refactors a working function on the way past, and hands back a diff three times the size of the problem. It isn't disobeying. It read an unbounded instruction literally and filled the gap with invention.
State the boundary as deliberately as the goal. Say what done looks like and what is out of scope in the same breath: “add the flag, don't touch the surrounding tool”; “fix this function, leave its callers alone.” The negative space is half the spec. With a human it goes without saying. With an agent nothing does.
How to practice it
Put the out-of-scope in the prompt.
“Add the flag, change nothing else.” Leave that out and the agent supplies its own.
Ask closed questions for facts.
“Does it pass, yes or no” gets a fact; “how's the code looking” gets an essay.
Use plan mode to see how wide it read the ask
before any edit, while narrowing is still free.
Bank standing limits in CLAUDE.md
(“never add dependencies or refactor unasked”) so the fence loads every session instead of being retyped.